This invention relates to mobile means of communication, and in particular to the ways and situations in which they are used.
In the most common mobile communication means systems, the base station controls the transmitted power of the mobile communication means on the basis of the received signal level. The transmitted power of a mobile communication means close to the base station is small, whereas at the limits of the coverage area the transmitted power is at its maximum. The current consumption of a mobile communication means is thus highly dependent upon the place in which the device is used.
Different obstacles, particularly in the immediate vicinity of the antenna, also attenuate the transmitter signal. The base station compensates for this attenuation by increasing the transmitted power of the mobile communication means. For example, a poor operating position of the mobile communication means, or having the antenna too close to the user's head, may cause an unnecessary rise in the current consumption. The same problem also arises when the user has turned so that his head lies between the base station and the mobile communication means.
A third factor affecting the intensity of the signal received by the base station is the position of the antenna of the mobile communication means. The base station antennae are typically arranged so as to transmit and receive vertically polarized signals, in which case the signal received by the base station is at its most powerful when the antenna of the mobile communication means is in the vertical position. If the user holds the mobile communication means diagonally or even horizontally, the signal received by the base station is thereby weakened, in which case the base station has again to increase the transmitted power.
An object of this invention is to create a system which directs the user of a mobile communication means to use his device in an optimal way. An object of this invention is also to create a system with the aid of which the user may avoid or shorten the length of a call when the power consumption of the mobile communication means is high. A further object of the invention is to create a system with the aid of which the user may maximize the battery charging interval. An object of the invention is also to create such a system with as little alteration as possible to current mobile telephones.